This invention relates to a method for constructing a glass panel of the type utilized in gaseous display technology, commonly called a "plasma" panel. Typical of such panels is a construction requiring multiple layers of glass to be bonded together, the respective layers containing conductor segments deposited thereon and/or predetermined voids or channels therein for enclosing a gaseous mixture. When constructed, such panels may be electrically energized via the conductor segments so as to create gaseous ignition in the voids between selected conductor segments and thereby produce a visual display which may be observed. Patterns of such gaseous ignitions are typically combined to form alphanumeric characters which are observable through the glass panel and are arranged along lines and/or columns to provide a meaningful alphanumeric display for communication purposes. Such displays may be energized and controlled by digital computers or other digital equipment and thereby provide a useful output device for such computers and other digital equipment. When coupled to and driven by an alphanumeric keyboard such displays provide a direct readout of the characters selected by depressing keys on the keyboard, and in combination therewith, serve as a useful input device for computers and other digital equipment.
Gas display panels have been utilized for the foregoing purposes, and have had various constructions. For example, U.S. Pat. Nos. 3,964,050, issued June 15, 1976, 3,860,846, issued Jan. 4, 1975, and 4,480,597, issued Mar. 21, 1978, disclose a number of constructional variations for such panels. Common to most of these gas display panels is the need to provide multiple glass layers which are selectively etched with voids and overlaid with conductor patterns along their respective facing surfaces and subsequently bonded together to form a unitary glass structure. A gas mixture is introduced into the voids created by the etching process, and the panel conductor segments are externally wired to voltage excitation devices for providing the voltage energization necessary to cause selective gaseous ignition. The manufacturing process for such panels is extremely precise and painstaking, for each manufacturing step involves a number of precision operations, and the construction of a typical display panel requires the cumulative successful execution of a considerable plurality of such manufacturing steps, any one of which if unsuccessfully completed results in an inoperative and useless display panel. Consequently great attention is directed to simplifying and improving the reliability of the various manufacturing steps so as to reduce the overall panel rejection rate which occurs during the manufacturing process. Since all of the manufacturing steps are cumulative, any improvement in reliability of a single step greatly enhances the chances of successfully producing a workable panel.
Construction of glass display panels of the type for which the present invention is best suited are panels having a plurality of gas channels etched into the glass layers for containing a gaseous mixture. It is typical that a plurality of such channels are etched along the surface of one glass section and a plurality of conductor segments are deposited along the surface of a facing glass section, and the etched channels and conductor segments are respectively orthogonally positioned relative to one another and the glass layers are subsequently bonded together to form a unitary whole which ultimately comprises the display panel. The techniques of bonding respective glass layers together have involved the utilization of a sealing glass which is initially applied as a paste along the edge surfaces of the facing glass sections, the glass sections then being carefully positioned in facing relationship and compressed together, and the assembly fired in an oven at a suitable elevated temperature such that the sealing glass melts into and becomes a bonded part of the glass sections. It is typical that this bonding process is accomplished prior to the introduction of a gaseous mixture into the internal voids of the display panel, and a means for introducing such gaseous mixture is typically provided. Once the gaseous mixture has been introduced into the voids in the panel the means for accomplishing such introduction is sealed to provide a completely enclosed panel having internal voids uniformly containing a gas mixture of the type selected for optimum display. The conductor segments are brought to the panel edges whereby external electrical conductors may be attached for applying the excitation voltages needed for controlling the display panel.